The present invention relates to a spring reverberator and an assembling method thereof; and, more particularly, a spring reverberator with components having a simple structure for improving the assembly productivity and an assembling method thereof.
In general, a variety of effectors are used in electric musical instruments or in a mixer for an audio in order to obtain dynamic, vivid sound effects. Among them, an apparatus for adding an echo to sound is called a reverberator. Although there are various kinds of reverberators, a spring reverberator is known to provide reverb effects in a relatively simple and inexpensive way.
FIG. 1 is a conceptual diagram of a spring reverberator according to the conventional art.
As shown in FIG. 1, a conventional spring reverberator 100 includes a driving transducer 10, a pickup transducer 20 and a coil spring 32 spanned between the transducers 10 and 20. In this conventional spring reverberator, the driving transducer 10 converts an audio signal inputted from a sound source into a mechanical vibration and transfers it to the coil spring 32, and the pickup transducer 20 converts the mechanical vibration transferred by the coil spring 32 into an audio signal added with a reverb effect produced from the coil spring 32 and outputs the signal.
FIG. 2 is a perspective view of the driving transducer 10 of the conventional spring reverberator shown in FIG. 1.
Referring to FIG. 2, the driving transducer 10 comprises a support frame 50 to which a magnetic core 70 is fixed. In order to serve as a magnetic circuit, the magnetic core 70 has a coil 72 at a middle leg 74. The support frame 50 comprises tubular portions 52 that are stretched out in the opposite direction to coil springs 32a, 32b, respectively. One end of a wire 65 extends into the tubular portion 52, and is soldered on a washer 66 that is pressed and held securely against a stop ledge (not shown) in the tubular portion 52. The other end of the wire 65 is formed into the shape of a hook 65a to be able to connect to the coil spring 32a. Near the hook 65a, an annular permanent magnet 62 is adhesively secured to the wire 65. To be more specific, the permanent magnet 62 is positioned in a magnetic gap between legs 72 and 74 of the magnetic core 70 (or in a magnetic gap between legs 74 and 76). In addition, a rubber damper ring 64 for absorbing the rotational vibration of the wire 65 is tightly fitted onto the wire 65 to be anchored at a predetermined position inside the tubular portion 52.
Referring again to FIG. 2, an assembling method of the driving transducer 10 in the conventional spring reverberator will now be described.
First, the annular permanent magnet 62 is slid over the wire 65 and adhesively fixed thereto near the hook 65a. Next, the damper ring 64 is tightly fitted to the wire 65 and pushed in the tubular portion 52 of the support frame 50, so that it can be anchored at a desired position in the tubular portion 52. Meanwhile, the magnet 62 on the wire 65 is positioned in a magnetic gap between the legs 72 and 74 (or in a magnetic gap between legs 74 and 76) of the magnetic core 70, with the magnet 62 being exposed out of the tubular portion 52. The other end of the wire 65 opposite to the hook 65a passes through the tubular portion 52 till it stretches outside of the tubular portion 52. The washer 66 is fitted onto the stretched-out portion of the wire 65 and then pushed into the tubular portion 52 until stopped by the stop ledge (not shown) in the tubular portion 52. Subsequently, the washer 66 and the wire 65 are soldered so that the other end of the magnet 62 is fixed to the support frame 50 via the wire 65. Further, the magnetic core 70, on which a coil-wound bobbin 76 is mounted, is fastened to the support frame 50 by a screw and the like. As mentioned earlier, the magnetic core 70 is arranged and fixed to the support frame 50 in order for the magnet 62 to be positioned in the magnetic gap between the legs 72 and 74 (or in the magnetic gap between the legs 74 and 76) of the magnetic core 70.
In the conventional spring reverberator, the driving transducer 10 and the pickup transducer 20 have substantially identical structures, so the pickup transducer 10 is assembled similarly to the driving transducer 10. More details are found in U.S. Pat. No. 5,539,830, which was granted to the present inventor.
As mentioned above, the conventional spring reverberator has disadvantages that a number of components should be assembled together in a given order, and the washer 66 and the wire 65 have to be soldered while the washer 66 is in tight contact with the stop ledge in the tubular portion 52, thereby requiring highly skilled manual dexterity and requiring a long time to assemble the components. Also, for accurate vibration of the permanent magnet 62, the axis of the permanent magnet 62 should be kept horizontal between the legs 72 and 74, or 74 and 76 of the magnetic core 70. However, in the conventional assembly process described above, the damper ring 64 and the washer 66 fitted tightly onto the wire 65 have to be pushed into the tubular portion 52 with the magnet 62 being fixed adhesively onto the wire 65 near the hook 65. Therefore, twisting stress is applied to the wire 65 during the pushing process, thereby twisting the axial direction of the magnet 62. Further, since the wire 65 is very thin (less than about 1 mm in diameter), it may be broken when the magnet 62 is turned to the opposite direction to adjust the twisted axial direction.
To resolve these disadvantages, the present inventor devised a support frame having a U-shaped boss (please refer to U.S. Pat. No. 5,539,830). According to this modified support frame structure, since the top of the tubular portion is open, the wire and a washer may be soldered easily, which resultantly reduces the assembly time compared with the support frame shown in FIG. 2. However, this modified support frame also does not solve the foregoing disadvantages, such as, the assembly has to be performed according to a specific given order, the axis of the magnet may be twisted, the damper ring is pushed over the wire in a predetermined position, and the assembly time is still somewhat lengthy.